#ifndef RFC822_PARSER_H
#define RFC822_PARSER_H

#include "unichar.h"

/* This can be used as a common NUL replacement character */
#define RFC822_NUL_REPLACEMENT_STR UNICODE_REPLACEMENT_CHAR_UTF8

struct rfc822_parser_context {
	const unsigned char *data, *end;
	string_t *last_comment;

	/* Replace NUL characters with this string */
	const char *nul_replacement_str;
};

#define IS_ATEXT(c) \
	(rfc822_atext_chars[(int)(unsigned char)(c)] != 0)
#define IS_ATEXT_NON_TSPECIAL(c) \
	((rfc822_atext_chars[(int)(unsigned char)(c)] & 3) != 0)
extern unsigned char rfc822_atext_chars[256];

/* Parse given data using RFC 822 token parser. */
void rfc822_parser_init(struct rfc822_parser_context *ctx,
			const unsigned char *data, size_t size,
			string_t *last_comment) ATTR_NULL(4);
static inline void rfc822_parser_deinit(struct rfc822_parser_context *ctx)
{
	/* make sure the parsing didn't trigger a bug that caused reading
	   past the end pointer. */
	i_assert(ctx->data <= ctx->end);
	/* make sure the parser is no longer accessed */
	ctx->data = ctx->end = NULL;
}

/* The functions below return 1 = more data available, 0 = no more data
   available (but a value might have been returned now), -1 = invalid input.

   LWSP is automatically skipped after value, but not before it. So typically
   you begin with skipping LWSP and then start using the parse functions. */

/* Parse comment. Assumes parser's data points to '(' */
int rfc822_skip_comment(struct rfc822_parser_context *ctx);
/* Skip LWSP if there is any */
int ATTR_NOWARN_UNUSED_RESULT
rfc822_skip_lwsp(struct rfc822_parser_context *ctx);
/* Stop at next non-atext char */
int rfc822_parse_atom(struct rfc822_parser_context *ctx, string_t *str);
/* Like parse_atom() but don't stop at '.' */
int rfc822_parse_dot_atom(struct rfc822_parser_context *ctx, string_t *str);
/* Like parse_dot_atom() but stops for '/', '?' and '='.
   Also it doesn't allow LWSP around '.' chars. */
int rfc822_parse_mime_token(struct rfc822_parser_context *ctx, string_t *str);
/* "quoted string" */
int rfc822_parse_quoted_string(struct rfc822_parser_context *ctx,
			       string_t *str);
/* atom or quoted-string */
int rfc822_parse_phrase(struct rfc822_parser_context *ctx, string_t *str);
/* dot-atom / domain-literal */
int rfc822_parse_domain(struct rfc822_parser_context *ctx, string_t *str);

/* Parse Content-Type header's type/subtype. */
int rfc822_parse_content_type(struct rfc822_parser_context *ctx, string_t *str);
/* For Content-Type style parameter parsing. Expect ";" key "=" value.
   value is unescaped if needed. The returned key is allocated from data
   stack. The value string is truncated for each call. Returns 1 = key/value
   set, 0 = no more data, -1 = invalid input. */
int rfc822_parse_content_param(struct rfc822_parser_context *ctx,
			       const char **key_r, string_t *value);

/* Decode a punycode-encoded domain name and return the UTF8
   form in result. Returns 0 on success and -1 on failure. */
void rfc822_decode_punycode(const char *input, size_t len, string_t *result);

#endif
